In the early part of the 20th century, Leon Theremin built a musical instrument whos pitch and volume could be controlled simply by waving one's hands around the device. U.S. Pat. No. 1,661,058 to Theremin (1928) describes this instrument. Since that time, a handful of refinements to the initial vacuum-tube design have been made to incorporate the evolving state of the art in the electronics circuitry. The device was redesigned around the silicon transistor and then again to take advantage of advancements in integrated circuit technology. Although each of these successively more modern designs has incorporated a different set of individual components, the basic mode of operation has remained largely unchanged. This class of musical instruments has come to collectively be known as “Theremins”.
Over time, the eerie sounds generated by these quirky instruments, together with their dramatic stage presentation, have attracted an avid cult following. Widely distributed Theremin performances can be heard in the Beach Boy's recording of the song “Good Vibrations” and as background music in any number of cheesy older horror movies.
Despite the broad enthusiasm however, there are surprisingly few accomplished Theremin practitioners or performers who are able to sustain an extended melody. Additionally, many of the followers of current Theremins complain about persistent problems encountered when working with the devices:
(1) Theremins are very difficult to build and maintain. In particular, many of the current Theremin designs require ongoing fine tuning by a technician familiar with the electronics' internal operation. Most Theremins are quite sensitive to temperature and humidity fluctuations and require frequent manual recalibration.
(2) Perhaps most importantly, current Theremins are incredibly difficult for the casual musician to play. Even accomplished musicians struggle to consistently perform moderately complex melodies on current Theremins. Current Theremins have no distinct keys, notes, or frets and a performer's command of “perfect pitch” is all but required to generate even a single desired note from a Theremin. This great chasm between interest in the instrument and ability to acquire the necessary skill to use one has begged for a solution virtually since its introduction.